Numerous technologies exist for measuring level of liquids or solids in an industrial process environment. Among these is a magnetic level indicator. A magnetic level indicator is constructed of a non-magnetic chamber, a float and a visual indicator. The chamber, also known as a cage or piping column, is essentially a pipe or similar device external to a process tank or vessel. The chamber is usually mounted vertically and is usually connected to the tank through two or more horizontal pipes. One of the horizontal pipes is near the bottom of the chamber and the other is near the top of the chamber. This arrangement allows the material level in the chamber to equalize with the material level in the tank, largely isolating the cage from agitation, mixing or other activities in the tank. The chamber can be isolated from the tank using valves. The float is sized and weighted for the specific gravity and pressure of the application and contain magnets which actuate a visual indicator on the outside of the chamber to indicate level.
A visual indicator in one known form comprises an elongate housing defining a rear wall and opposite side walls. End caps provide a top wall and a bottom wall. The housing has a front opening. A flag type indicator assembly or a shuttle type indicator assembly is contained in the housing. A rectangular flat bezel indicator covers the front opening. The visual indicator is clamped on the chamber. The individual flags or the follower contain an alignment magnet which couples with the float magnets as the float moves up or down within the chamber. Float movement rotates the flags and changes their color or, in the case of a follower, moves the follower to the point of the level, as is known.
The flat bezel is typically of a transparent material and printed with indicia representing a measuring scale for material level. The position of the follower or the point at which the flags change color represents true level. True level is indicated or read by the corresponding point on the measuring scale. To keep condensation out of the housing it is necessary that the housing be sealed. A Schrader valve is then used to provide a dry nitrogen backfill. The flat bezel must be sealed along its circumference including the side edges and opposite ends. This type of seal is an extremely difficult seal to achieve, particularly in the four square corners where the bezel and the end caps meet. Generally, a reliable seal can only be achieved using some form of caulking or adhesive. Additionally, any flexing or twisting of the housing that occurs during assembly can cause the two seals along the length of the bezel to release allowing a loss in positive purging pressure of dry nitrogen.
The traditional flat bezel design also requires that there be some sort of locking/holding component to secure it to the housing. This may be a channel in the side walls. There must be sufficient material or thickness to provide a sufficient amount of strength to hold the flat bezel in position. This requirement causes the indicator assembly to be positioned to the rear of the housing thus limiting the indicator viewing angle.
The present invention is directed to overcoming one or more of the problems discussed above in a novel and simple manner.